1. Chapter 14: Interactions in the Ecosystem

2. Niche versus Habit? Habitat Niche Includes Food Abiotic conditions
describes all of the abiotic and biotic factors in the area where an organism lives
Niche
All the biotic and abiotic factors that a species will need to survive and reproduce
Includes
Food
Abiotic conditions
Behavior

3. Habitat versus Niche

4. What kind of interactions can organisms in the same community have ?
Think of how you interact with people you know. What kind of interactions are they? Friendship Competitor Enemy No relationship

5. Community Interactions
Competition
Two organisms fight for the same limited resources
Food
Space
Mates
Oxygen and Sunlight

6. It decreases and then the prey decrease
Predator – Prey Relationship
One species captures and feed on another
What happens when the prey population increases to the predator population?
What happens when the predator population increases to the prey population?
The two are directly proportional to each other
It increases also
It decreases and then the prey decrease

7. Symbiosis
Close relationship between two or more organisms of different species which interact with each other

8. Mutualism
Both benefit from the interaction

9. Commensalism
One organism benefits from the relationship and the other is unharmed

10. Parasitism
One organism benefits and the other is harmed

11. Carrying Capacity
Is the maximum number of individuals of a particular species which the environment could support
When year did the population first reach carrying capacity?
What is the carrying capacity for this population size?
What is your prediction for population size immediately following WWII?
~1850
~1.6 million people
It will decrease

13. What ecological factors limit population growth?
Density- Dependent limiting factors
Limiting factors that are affected by (dependent on) the population’s size
Competition – limited resources causes a struggle for survival (Darwin!!)
Predation – as the predator’s population increases, the prey population decreases
Parasitism and disease – the three things that control a population’s size are war, disease and famine!! (Malthus!!)

15. Density – Independent limiting factors
Factors in the environment that limits a population’s growth that have nothing to do with (independent of) the size of the population
Weather
Natural disasters
Human activity

16. Density dependent or density independent factors?
Competition between members of population.
Predation.
A hurricane drowning many earthworms
Disease
Burning of a forest
A very cold winter
Density Dependent
Density Dependent
Density Independent
Density Dependent
Density Independent
Density Independent

17. What follows the Natural Disaster?
Succession
A sequence of biotic changes that regenerates a damaged community or a bare, new area
What follows a forest fire?
What happens after a volcano?
What occurred after the asteroid hit the earth?

18. Primary Succession starts from bare rock
Pioneer species are the first to inhabit the area
Lichens and mosses
Break down minerals in rock to allow for soil to build up
Soil gets thicker and now grasses can start to grow.
Next comes small shrubs then trees
Final community is the CLIMAX community which are large trees like Oaks and Pines

19. Climax species
Pioneer species

20. Secondary Succession starts from soil
Usually occurs in areas that have been disturbed
Bulldozed or cleared area
Fire
Flood
Hurricane

21. Climax species
Pioneer species